Contact Allergen of the Year: p-Phenylenediamine

Vincent A. DeLeo


Dermatitis. 2006;17(2):53-55. 

In This Article

New Route of Exposure

Henna has been used for centuries in certain cultures as body paint and more recently as a hair coloring agent. It has been noted to be a very low-level sensitizer.[12] At the same time, body tattooing has enjoyed increased acceptance among the youth of many cultures, including those in the West. A recent phenomenon is "temporary tattooing," in which the tattoo colors the stratum corneum and lasts until that layer is shed. Such tattoos are usually referred to as henna tattoos or black henna tattoos. Recently, reports of reaction to these temporary henna tattoos have become common. In the vast majority of such cases, the offending allergen has been found to be PPD. The level of PPD in these products is much higher than that found in hair color.[19,20,21,22,23] Because of PPD's high sensitization potential, the application of PPD to the skin is not an approved use. Since sensitization to PPD from tattoos is likely to be lifelong, we will likely see a population of individuals who will respond adversely to their attempts at hair coloring as they age. Because sensitization from such high concentrations in these tattoos leads to a very low threshold for elicitation, testing with the standard 1% concentration may lead to severe reactions, and it has been suggested that testing be done with concentrations of 0.01 to 0.30%.[24]


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